It's a great time to vista WDW.
MK has a special fireworks show which they usually present in July 3 and 4.
Epcot does Illuminations followed by a Fourth of July show on July 4 only. When I went a few years ago, there was also a big Voices of Liberty concert in the afternoon.
DHS has a fireworks show on July 4 only. Didn't see that, so I don't know much about it.
Search on Allears.net. They probably have a lot of specific info about Fourth offerings in the parks and at resorts.
Whatever you choose, get to the park early, be prepared for big crowds and long lines. I'd recommend making an ADR for a late lunch/early dinner buffet. Use it as a chance to relax, enjoy AC and free refills, regroup for the night's festivities.